/Engine/Source/Runtime/Core/Public/Serialization/PackageWriter.h
Helper callback type for Writers that need to send the message on toUCookOnTheFlyServer.
typedef [TUniqueFunction](API\Runtime\Core\Templates\TUniqueFunction)< EPackageWriterResult([FBeginCacheForCookedPlatformDataInfo](API\Runtime\Core\Serialization\ICookedPackageWriter\FBeginCacheForCo-) &Info)> FBeginCacheCallback